Abstract: The fixed dunes with 30% vegetation coverage and the semi-fixed dunes with 10% and 15% vegetation coverage were selected as the typical plots in the Mosuowan oasis-desert ecotone in the southwestern marginal zone of the Gurbantunggut Desert. The purpose of the study was to reveal the relationship between soil chemical properties and vegetation in the temperate fixed and semi-fixed desert. Soil samples were collected from different parts of dunes to test soil pH value, electrical conductivity, organic matter content, total nitrogen content and total phosphorus content in laboratory. The results showed that: ① With the decrease of vegetation coverage, the soil pH value, electrical conductivity, organic matter content, total nitrogen content and total phosphorus content were decreased gradually on the western and eastern slopes as well as the top of the longitudinal dune; ② Distribution patterns at different parts of different longitudinal dunes were different. The maximum pH value, electrical conductivity, organic matter content, total nitrogen content and total phosphorus content of both the longitudinal dune A and B occurred in the inter-dune land, but there was no obvious regularity in other parts. The maximum pH value and electrical conductivity of the longitudinal dune C occurred in the inter-dune land, while the maximum soil nutrient content occurred on the dune top; ③ The distribution trend of soil properties in different layers of dune was relatively consistent. The soil pH value and electrical conductivity were increased with the increase of soil depth, while the soil nutrient content was decreased with that; ④ The spatial distribution heterogeneity of soil chemical properties was closely related to the distribution pattern of vegetation, and they interacted each other. When the vegetation coverage was high, the biological effect played a dominant role; when the vegetation coverage was low, the abiotic factors, such as wind erosion and topography, played an important role in enhancing the biological effects, and vegetation intercepted and enriched the soil particles and nutrients.

Key words:  desert-oasis ecotone; vegetation coverage, soil chemical property, spatial distribution; Gurbantunggut Desert